All Gays Are Promiscuous: Most of the cast tends to avert this, but Shane is this trope distilled into human form. Most of Bette's problems over the course of the series are caused by her poor judgement and self-control when it comes to sex. Sooner or later, she cheats on every partner she ever has, and Alice even calls her out on it at one point.
All Lesbians Want Kids: Bette & Tina's decision to procreate, and all the resulting drama which ensues, is one of the major plot threads throughout the entire run of the series. Averted with pretty much all other characters who frankly have enough problems as it is
Jenny and Dana were based loosely on two of the creators of the show, Michele Abbott and Kathy Greenberg. The subsequent treatment of both characters over the course of the show's run could be interpreted as a Take That (see Evil Former Friend below).
Bastard Understudy: Adele, Jenny's personal assistant, displaced her as the producer of LezGirls through blackmail.
Batman Gambit: It probably would have been more difficult for Adele to get her Magnificent Bastardry on if she couldn't count on S5 Jenny acting selfish, irresponsible, and just plain terrible at every opportunity.
In Season 1, Dana and her tennis partner Harrison act as beards for each other, since neither one is out of the closet.
In Season 5, Niki's agents insist that she use her male costar as a beard, as damage control after Alice outs her on national television. She caves under the pressure, which drives a wedge between her and Jenny.
Jennystarts off straight, until a kiss from Marina makes her see the lesbian side of Sears. After spending the better part of a year wrestling with her sexual identity, she admits to having had lesbian tendencies (which she tried to suppress) all her life. A girlfriend or two later, she winds up involved with female-to-male transsexual Max. After their relationship implodes, she swears off of men altogether.
Tina had only ever been with men before she hooked up with Bette. Several years later, she found herself craving male companionship again, but less than a year after that she drifted back to women. Her stated "regrets" about going back to men were social rather than sexual; she missed her place in the lesbian community and felt betrayed when those lesbian friends ostracized her. She has maintained and enjoyed multiple on-screen relationships with both women and men. So it's likely that Tina is a bisexual woman who rounds herself up to "Lesbian" for political reasons.
Alice gives lip service to being bisexual in Season 1. The one actual relationship (as opposed to casual hookup) she had on-screen with a male-bodied character was the "male-identified lesbian" Lisa, who, as Alice described, "did 'dyke' better than any dyke [she] had ever met" (it was not a compliment). After the first season, no heterosexual relations involving Alice are seen or described, and in Season 5, Alice claims under oath to be a lesbian, whereas the gaydar in the season 5 opening identified her as bisexual.
In Season 3, episode 2, Jenny tazes a homophobic bully who was assaulting Moira and shouts "We're dykes, not fags".
Brother-Sister Incest: During the after-show "Interrogation Tapes", Tina revealed, that Bette was not her first lesbian experience, but that it was her own sister, whom she had that kind of relationship (judging by Tina's words, it was less about romance than about "experimenting"), when she was from about 11/12 until 15 years old.
Moira appeared to be one until he came out as Max.
Shane arguably qualifies as butch. She doesn't think of herself as one, as evidenced by her bemused but slightly puzzled reaction in an episode where she and Max help carry some luggage for the others, and Max refers to both himself and Shane as "butches."
But I Would Really Enjoy It: Phyllis says this to Bette after coming out as a lesbian and leaving her husband thanks largely to Bette's influence. She realizes nothing is ever going to happen between them, though.
But Not Too Black: Both Bette and Kit have biracial parentage, but Kit is darker-skinned. Bette and Kit had different mothers. Kit's mother was- presumably- black, as evidenced in the first episode: during an introduction at a party, Bette makes it a point to mention that Kit is her half-sister, to which Kit replies, "Guess which half?"
California Doubling: Inverted - The series took place in Los Angeles, but was filmed in Vancouver. Lampshaded at one point in Season 5, when Jenny is scouting locations for Lez Girls, and loudly proclaims that "Vancouver can't pass for L.A.!"
Chuck Cunningham Syndrome: Lisa, the male-identified lesbian, vanishes without a trace after Alice dumps him. He is never mentioned again.
Mark probably got Chucked the worst of all on this series. In season two, he's part of the main cast, gets a decent amount of character development, and reaches an almost familial level with the girls. The last time we see him is in the season two finale at Bette's dad's funeral. He is absent the following season and is never mentioned again, despite having been Shane and Jenny's roommate.
It's entirely likely that they cut him out of their lives completely, considering what he did to them.
Cure Your Gays: When Jenny & Shane are interviewing potential roommates in Season 2, one of them makes this offer, and she is shown the door.
Dark and Troubled Past: The physical and sexual abuse Jenny suffered as a child is explored, but never defined, in one of the major plot threads of Season 2. Shane's dark past is not focused on as much, but is still mentioned. In Seasons 1-2, we learn that she was once forced to work as a (pretending-to-be-male) prostitute, that she was essentially abandoned by her parents, has various drug addictions, etc. These events are strongly implied to be the reason she is such a loyal friend, but terrible with relationships/commitment - she feels the need to please others, is satisfied with very little for herself, but is afraid to commit to anyone or anything. The later seasons continue to add heartbreaking details - Shane is thrilled to simply have her own, tiny little room because she's apparently never had her own before. (In Season 6, Jenny, of course, promptly converts Shane's room into a study one day when Shane is out, assuming that since they're now sleeping together, she'll just move into Jenny's room with her!)
Demoted to Extra: In Seasons 1-5, Kit was one of the main characters. In Season 6, she existed primarily to say "Girl!" about once per scene. After two seasons of being a core member of the cast, Jodi also fell into the background during Season 6.
Double Standard: Rape, Female on Female: After Tina finds out about Bette's first affair and confronts her about it, Bette rapes Tina in an attempt to make up for it...buh-what? As the trope implies, after the fact, the rape isn't brought up again.
Drugs Are Good: Most of the cast is shown using some form of marijuana at various points, and Shane even dabbles in harder drugs, to no ill effect. However, this trope was played straight in a Season 1 subplot involving a friend of Shane's who wound up consumed by his addictions. Unlike Shane, he couldn't handle his drugs. Niki using drugs is alluded to.
Dysfunction Junction: Just try to find one character on this show that isn't massively screwed up, even the successful and wealthy ones.
Ensemble Cast: Bette, Shane, Alice Jenny and Tina all get significant amounts of screentime.
Even the Girls Want Her: Shane. But kind of a moot point in a Cast Full of Gay, but even the straight girls go gay for Shane. Interestingly, Shane's based off a real woman named Sally Hershberger, also a hairstylist for celebrities- though her clients include far more 'big names' than Shane's, including multiple Presidents. She's also known for making even straight celebrities feel the urge to experiment a little, so perhaps the portrayal isn't that unrealistic.
Face-Heel Turn: Jenny makes one somewhere between the end of Season 3 and the beginning of Season 4, with no real explanation given. Arguably, her Suddenly Sexuality in Season 1 overlaps with this - Jenny seems like the perfect girlfriend at first, so it's a surprise when she turns out to be so willing to immediately cheat on Tim when she realizes her attraction to girls. Don't forget all the times she lied to and manipulated both TimandMarina over the course of the affair and the aftermath, alternating between trying to convince them that it was their fault and playing the victim while she bounced back and forth between the two of them like a rubber ball.
Fille Fatale: Nadia was legally an adult, but her position as Bette's student and employee made their affair professionally and socially inappropriate. Despite (or because of) this, Nadia pursued Bette relentlessly (and sexual self-control wasn't exactly one of Bette's defining traits).
Max in Season 3, when Jenny picks him up in her hometown and brings him back to L.A. with her.
Flanderization: Much of the cast, but especially Shane. Bette went from "classy yuppie who knows how to cut loose every now and then" to "stick in the mud so uptight it's a wonder any of her friends bother with her at all."
In the pilot, they mention that having a longer ring finger than index finger is a hint that someone may be a lesbian (which is Truth in Television). On Jenny, they are exactly the same size. Alice mentions that this might mean she's bisexual. Just a few minutes later...
Jenny wears a necklace with the Hebrew letters "חי", meaning "life" in Hebrew. But she is always wearing it in backwards (Hebrew is read and written from right to left). This is most likely a foreshadowing for the opposite of live, death (her death later in the series).
Gayngst: Dana during most of Season 1, when she was still in the closet, mostly on account of her conservative parents and Smug Snake manager. As it turned out, said closet was even more transparent than she realized.
Genre Shift: Apparently what this primetime lesbian soap opera really needed to do in its final season was introduce a murder mystery. Which never got solved.
Girl on Girl Is Hot: Exploited. Due to featuring a lot of sex scenes between women, the show has a very large male fanbase whose primary motivation for watching it is... yeah. The show got often accused of Pandering to the Base because of said Misaimed Fandom. Writers eventually performed a Take That, Audience! with Mark's attitude towards Shane and Jenny to a mitigated reaction from the audience.
The Alice/Dana/Tonya love triangle was an important (and well-executed) subplot from the latter half of Season 1 through the first half of Season 2. The conclusion was a poorly-written anticlimax that came way out of left field. A superb performance by Erin Daniels only served to highlight the awful writing.
Hero Antagonist: Helena Peabody in Season 2. She was a villain from Bette's point of view. But giving money to charity isn't evil just because you're not giving it specifically to the PoV character's company. And it's not "stealing your girlfriend" if your girlfriend already broke up with you, because you cheated on her. In Season 3, Helena quickly makes the transition to full-fledged protagonist, a status she maintains for the rest of the series.
Except the problem with Helena was that she was originally presented as almost like this predator of pregnant women. She had children, but they weren't her biological children. She had stayed with her previous girlfriend long enough for the woman to give birth to two kids, and then dumped her and used her influence as a philanthropist to get primary custody of the kids. It was heavily implied that she was attracted to Tina because Tina was pregnant, and may have eventually tried to steal Tina's daughter from her. Once Helena joined the main cast and she got her much-needed Character Development this whole backstory just sort of disappeared, but Bette had plenty of reason to be concerned.
Jenny's creative writing instructor in Season 2 (played by real-life lesbian Sandra Bernhard) is pretty much the opposite of this.
Bette becomes this trope in Season 4, when she joins the university faculty. It does not end well for her (see Teacher/Student Romance below).
Hurricane of Euphemisms: A truly staggering number of euphemisms for vagina are listed by the regulars at the end of the first episode of season three, featuring such terms as "bikini biscuit," "breakfast of champions," and "munch box" and probably 30 or so more.
The Hyena: Weezie, the contractor who does the extensions on Bette and Tina's house, so they have enough space for their child, who's gonna be adopted. Bette and Tina's Gaydar doesn't work on her and leaves them extremely confused.
I Don't Pay You to Think: In "LGB Tease," Jenny delivers this line rather awesomely after Marissa brings back her dog wearing the wrong color ribbons:
Jenny: (regarding her dog) What's this on his head? This is mauve. This is not orange.
Marissa: Well, the groomer ran out of orange, so we thought we would...
Jenny: No. No, no. I don't pay you to think. (to the dog) Do I, Sounder? Do I pay her to think? (to Marissa) He hates you. So take him back to the groomers now and get orange ribbons so that he can like you again. That's it.
Incompatible Orientation: A rare variant with Jenny and Max, who is unable to accept him being a trans man since she's a lesbian and Max is technically a straight man.
Tina helping Bette get (and stay) back together with Jodi in Seasons 4-5. She wins in the end, though.
Shane chasing Molly away at the end of Season 5. A particularly tragic example, since she was one of only two women Shane had ever really loved. And unlike Carmen, Molly actually accepted Shane for who she was.
Helena's affection for Dylan in Season 3 appeared to be unrequited because of this, but as the season progressed the situation proved to be a lot more complicated than that.
Season 5 introduced Molly, the one straight girl on the planet who won't go gay for Shane...until she does.
In the Blood: Shane's father is also a womanizer, but unlike Shane, he's consciously and actively malicious. Yet he still manages to convince her that they're the same, which winds up ruining her relationship with Carmen and Paige.
Karma Houdini: Mark. When he's rooming with Jenny and Shane, they find out he's hidden cameras all over the house and has been secretly recording every aspect of their lives. Somehow, he avoids being stabbed or thrown in jail. They do tell him to leave, but within the same episode, Jenny changes her mind and dares him to stay and atone. Because, y'know, a real woman would do that.
In the last two seasons, Adelle gets away with identity fraud, blackmailing an entire studio, and turning an original pro-gay film into an easy-sell Chick Flick against the wishes of the original creative team. The only plausible reason she gets away with her crimes was because the ultimate victim was Jenny.
Mark to Shane in Season 2, before his betrayal was revealed.
Lisa the male-identified lesbian is introduced as Shane's Lez Bro before he starts dating Alice.
Lipstick Lesbian: Most of the cast, quite deliberately. Ilene Chaiken publicly claimed that the show would never have been made if it hadn't pandered to the Male Gaze (and unfortunately, she's probably right). However, that isn't necessarily a bad thing. The show seemed to have a well-rounded group of lesbians who were feminine, butch, or somewhere in between. The fact that the show had so many overtly feminine lesbians was fairly groundbreaking, in having so many non-stereotypical lesbians. And it seemed even less about "lipstick lesbians" than it was simply "women who have different styles of dress." Shane dresses in an androgynous and punk rock way, Bette is fond of prim suits and button-down shirts, Alice is girly with a tomboyish streak, Jenny is overtly girly most of the time, Dana seems to be somewhere between tomboy and girly, and Tina seems to have a bit of a boho thing going on.
Locked in a Room: After Bette and Candace are locked in a jail cell, they have an extremely hard time not to jump each other's bones (they still do it, after they're out of jail and that breaks up Bette and Tina's relationship).
During a heat wave, accompanied by power outages, Bette and Tina got stuck in an elevator. They got eventuall back together.
Kate Moennig has stated at every opportunity that the biggest difference between her and Shane is that Moennig isn't a super-promiscuous compulsive cheater.
Mia Kirshner, despite playing the selfish, narcissistic and pretentious Jenny, runs a charity intended to help people in third-world countries.
Eric Lively passed up a spot in the main cast of 24, one of the most popular and longest-running network television dramas of all time, for one season of a niche-market premium cable show. He did this because he believed in what The L Word was trying to do in general, and specifically with Mark's subplot, and thought the more important cultural contribution trumped fame and fortune. He's pretty much the polar opposite of Mark, who is (justifiably) the most hated character in the history of the series (and what the viewers will always remember him for). Incidentally and several years later, Lively did end up appearing in 24's "Redemption" TV movie as President Taylor's son Roger, who is "murdered" by the eventual conspirators of the forthcoming season.
Meat-O-Vision: Shane experiences Sex-O Vision; When she goes swears off sex, she starts to hallucinate every women in her field of view as naked and willing.
Money Fetish: Helena and Catherine play with their winnings from gambling, which leads to fetishistic sex with it.
Holland Taylor is practically typecast in this role.
Mr. Seahorse: Max gets pregnant while transitioning to male (and looks quite masculine due to the hormones he's been taking).
My Secret Pregnancy: In season 2, Tina tries to hide her second pregnancy from Bette, afraid of the pain it would cause if Tina experiences another miscarriage.
Negated Moment of Awesome: When Jenny and Shane find out about Mark secretly filming them, he tries to tell them how much he's "grown" since he set up those cameras. Jenny retorts, "You think that's what I'm here for? For some fucking man to chew up and spit out so he can 'grow'?!" It was actually pretty badass (and this was Jenny, for God's sake) and could have been a Crowning Moment Of Awesome if she hadn't decided at the end of the episode to fold and give him another chance.
Nice Guy: Surprisingly, most of the male characters.
In Season 1, Tim seemed like the perfect boyfriend at first. After walking in on his so-called friend fucking his fiancée, he acted like a huge jerk. But most people would consider that a reasonable response. And even at his worst, while standing next to Jenny, the woman who spent half a season deceiving, manipulating, humiliating and cuckolding him during her journey of sexual self-discovery, he looked like a saint.
In Seasons 3-4, Angus played this trope ridiculously straight. But when he finally did fall off his pedestal, he fell hard.
Sunset Boulevard is not only a straight guy, but he's also probably the only genuinely decent man Kit has ever dated.
Parental Abandonment: Shane's absentee junkie parents screwed up her ability to form and maintain functional romantic attachments in a big way. And when Dad finally did come back into her life, he only managed to mess with her head even more.
Played literally with Shane's half-brother Shay, whose mother leaves him on Shane's porch never to return.
Bette skates into this at her worst. Chronic cheating aside, she did not take Tina's bisexuality crisis well. Getting mad at your ex for leaving you for a man is one thing. Trying to get sole custody of your child behind the birth mother's back is another thing entirely. As is kidnapping said daughter when Tina found out and called her out on it. See also Double Standard: Rape, Female on Female.
Put on a Bus: Marina, Robin, Carmen, Lara, Paige, Papi, Catherine...The show pruned away at least one or two characters every season.
Strip Poker: In "Lesson Number One," Helena plays strip gin against Catherine in an attempt to clear her gambling debts.
Suddenly Sexuality: Jenny. Phyllis. Tina getting together with Bette can also be seen this way, as her coming out story during an episode in Season 1 mentions explicitly that Bette was the first, and at the time of that episode, the only woman Tina had ever been with.
Take That, Audience!: Unsuccessful. Despite trying to dodge the virulent accusations of pandering to a straight male demographic by featuring an in-show betrayal from Mark towards Shane and Jenny who only got with them because he thought Girl on Girl Is Hot, the true lesbian audience remained unconvinced.
Teacher/Student Romance: Bette's brief affair with her assistant Nadia in Season 4. Phyllis fires Bette over it at the beginning of Season 6.
Truth in Television: Leisha Hailey, Clementine Ford, Tammy Lynn Michaels, Guinevere Turner, Jane Lynch, Alexandra Holden, Kelly McGillis, Kristanna Loken, Daniela Sea, Karina Lombard and Heather Matarazzo are all lesbian or bisexual in real life, as well as playing lesbian or bisexual characters on the show (and Mia Kirshner has hinted at bisexuality in interviews).
Kate Moennig is fiercely private about her personal life and refuses to comment on her sexual orientation. But Jennifer Beals may have accidentally outed Moennig in an interview she did with The Advocate. And there have been rumors of Moennig being involved with Francesca Gregorini and her co-star Clementine Ford (which Ford denies).
She's been pretty blatant about her involvement with Holly Miranda on Twitter.
More recently, suspicions has also arisen about Rose Rollins, who played Tasha, and is now in another show where she will play a lesbian role.
The deaf Jodi Lerner is played by Marlee Matlin, who's deaf in Real Life.
Your Cheating Heart: Pretty much all of the characters sleep around behind each other's backs, beginning in the very first episode with Jenny and Marina.
You Monster!: Bette, when Fae Buckley brings up Tina's stillborn child in a debate and claims that god killed Tina's unborn child, because they were lesbians and god wanted to spare it from being raised by lesbians (which was partly provoked by Bette pulling out a video cassette with a porno video, were the 17-year-old Fae Buckley a.k.a. "China" starred. She ran away from an abusive home and survived as a prostitute and porn actress).